1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * Based on reduced version of METAG
6 */
7
8
9#include <linux/init.h>
10#include <linux/reboot.h>
11#include <linux/memblock.h>
12#include <linux/of.h>
13#include <linux/of_fdt.h>
14#include <asm/mach_desc.h>
15#include <asm/serial.h>
16
17#ifdef CONFIG_SERIAL_EARLYCON
18
19static unsigned int __initdata arc_base_baud;
20
21unsigned int __init arc_early_base_baud(void)
22{
23 return arc_base_baud/16;
24}
25
26static void __init arc_set_early_base_baud(unsigned long dt_root)
27{
28 if (of_flat_dt_is_compatible(node: dt_root, name: "abilis,arc-tb10x"))
29 arc_base_baud = 166666666; /* Fixed 166.6MHz clk (TB10x) */
30 else if (of_flat_dt_is_compatible(node: dt_root, name: "snps,arc-sdp") ||
31 of_flat_dt_is_compatible(node: dt_root, name: "snps,hsdk"))
32 arc_base_baud = 33333333; /* Fixed 33MHz clk (AXS10x & HSDK) */
33 else
34 arc_base_baud = 50000000; /* Fixed default 50MHz */
35}
36#else
37#define arc_set_early_base_baud(dt_root)
38#endif
39
40static const void * __init arch_get_next_mach(const char *const **match)
41{
42 static const struct machine_desc *mdesc = __arch_info_begin;
43 const struct machine_desc *m = mdesc;
44
45 if (m >= __arch_info_end)
46 return NULL;
47
48 mdesc++;
49 *match = m->dt_compat;
50 return m;
51}
52
53/**
54 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
55 * @dt: virtual address pointer to dt blob
56 *
57 * If a dtb was passed to the kernel, then use it to choose the correct
58 * machine_desc and to setup the system.
59 */
60const struct machine_desc * __init setup_machine_fdt(void *dt)
61{
62 const struct machine_desc *mdesc;
63 unsigned long dt_root;
64
65 if (!early_init_dt_scan(params: dt))
66 return NULL;
67
68 mdesc = of_flat_dt_match_machine(NULL, get_next_compat: arch_get_next_mach);
69 if (!mdesc)
70 machine_halt();
71
72 dt_root = of_get_flat_dt_root();
73 arc_set_early_base_baud(dt_root);
74
75 return mdesc;
76}
77

source code of linux/arch/arc/kernel/devtree.c